more complicated, but single chain coupling 7s, 9s, and 1s:2. (7)d9=d6-a6=b4-bd9=(7-9)h9=g7-g456=h5-e5=(1348)def5e-(1)b5=(1-7)b4=a6 => d6<>7UP=81

22/Jan/11 2:23 AM

I should have shortened that last chain, eliminating the segment g7-g456:2. (7)d9=d6-a6=b4-bd9=(7-9)h9=h5-e5=(1348)def5e-(1)b5=(1-7)b4=a6 => d6<>7UP=81

22/Jan/11 2:55 AM

Apologies for typo: def5e should be def5e6.corrected:2. (7)d9=d6-a6=b4-bd9=(7-9)h9=h5-e5=(1348)def5e6-(1)b5=(1-7)b4=a6 => d6<>7UP=81

22/Jan/11 3:34 AM

Hi kobold,I'm not sure but I feel that I know you by your style... I think that you’re one of the best player here (like Steve, rwm, Dave and one you know: farpointer – what a sad...), your talent can hepl many players here to improve their skills on solving tough puzzles. So, I hope you live here forever...

22/Jan/11 3:34 AM

as has been pointed out, a complex chain can sometimes be represented more simply as a kraken; grouping is more efficient, and can eliminate dynamic aspects, too:2. kraken row (7)bdh9 => d6<>7 ; UP=81(7)b9-b4=a6||(7)d9||(7-9)h9=h5-e5=(9-7)h9=h5-e5=(HP(79)-1)be4=(1-2)f4=d6

Hi Jim. I posted a long chained solution for 26 Jan 2009, and made some comments on your impressive proof. You even found a rare 4 possibility kraken there.How do you spot all these krakens ? Is there a pattern you look for, or is it a hard, trial and error slog ?Regards, Alfred.

Alfred, thanks for spotting the errors on my solution for 26 Jan 09. You are correct on all counts. You are a good proof editor.

22/Jan/11 11:16 AM

Alfred, as far as krakens go, I guess it is a matter of practice more than anything else. I also have been reading a lot of commentary here and on the UK sudoku forum. There are several good solvers who post regularly to the UK site. That has helped a lot. I think you can see my solving methods More...

22/Jan/11 11:45 AM

Re: archeaology. When I look back at my early efforts (22 Jun '10), I cannot understand what I wrote, not just because it was confused, but primarily because it wasn't written in eureka.

22/Jan/11 11:54 AM

June 11,2010 SE=8.5 is challenging. had to use a quantum link (garden variety) and then a looped kraken to get over the hump (noticed even farpointer was stumped by this one back in the day).

22/Jan/11 2:05 PM

Hi Jiminoregon (and all),

I think you have (indirectly) said in your 11:54AM post, a really key piece of information -

- Eureka is to communicate the solver's thinking (aka, solution/proof) to other people (and maybe to themselves as well).